Bruce Springsteen contributed a new song called "Freedom Cadence" to the closing credits of the movie Thank You for Your Service.

The film, which opened Friday, focuses on Iraq war veterans suffering from Post-Traumatic Stress Disorder as they try to return to civilian life. American Sniper's Jason Hall wrote and directed the movie, which is based on David Finkel's book of the same name.

You can listen to Springsteen's "Freedom Cadence" below.

In a recent interview with the Springsteen fan site Backstreets, those involved with the film revealed how the song came about, explaining that Adam Schumann, the real-life subject of the book, "had a cadence that they sang in boot camp, and Jon [Kilik, the movie's producer] recorded him singing it on his cellphone," Hall said. "Jon is friends with Bruce and played it for him. Bruce was like, 'Oh, that's cool. How'd the movie turn out?' 'Movie turned out great.' We played him the movie. Bruce loved it, watched it twice and then said, 'Send me that recording, come back in a month and bring that kid.' So Adam went up there with Jon and recorded the song with him."

The song is based on the "Freedom" marching cadence, which is better known as "Some Say Freedom Is Free" and credited to PFC Roger L. Southard. It's a cadence passed down through generations of soldiers, with lyrics changed through the years, according to Schumann. "Once you hear a cadence in basic training, it just becomes that mantra in your head, so you carry that on wherever you go, and then when you've got guys under you and you're calling cadence, you call the same one," he noted. "So it's just passed down through generations, but changed from time to time."

Springsteen did make some changes to the lyrics, which at times recalls his classic "Born in the U.S.A." He recorded "Freedom Cadence" at his Stone Hill Studio in New Jersey, with Schumann and Kilik helping out on backing vocals. According to U.S.A. TodaySpringsteen plays harmonium and banjo on the track, while his co-producer, Ron Aniello, programmed drum loops and keyboards. (Aniello also produced Springsteen's 2014 album High Hopes and 2012's Wrecking Ball, as well as Springsteen's wife, Patti Scialfa, and her 2007 album, Play It as It Lays.)

From his protest songs, like "Born in the U.S.A.," to his annual appearances at the Stand Up for Heroes benefit, Springsteen has long supported veterans causes.